2nd try

Dockerfile

@@ -1,22 +1,24 @@
 FROM ghcr.io/linuxserver/duplicati:2.1.0
 
-apt-get update
-sudo apt-get install ca-certificates curl
-sudo install -m 0755 -d /etc/apt/keyrings
-sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc
-sudo chmod a+r /etc/apt/keyrings/docker.asc
+SHELL ["/bin/bash", "-o", "pipefail", "-c"]
 
-# Add the repository to Apt sources:
-echo \
+
+RUN apt-get update -y \
+  && apt-get install -y --no-install-recommends \
+  ca-certificates \
+  curl \
+  && rm -rf /var/lib/apt/lists/* \
+  && install -m 0755 -d /etc/apt/keyrings \
+  && curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc \
+  && chmod a+r /etc/apt/keyrings/docker.asc \
+  && echo \
   "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu \
   $(. /etc/os-release && echo "${UBUNTU_CODENAME:-$VERSION_CODENAME}") stable" | \
-  sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
-sudo apt-get update
-
+  tee /etc/apt/sources.list.d/docker.list > /dev/null
 
 # Install Docker CLI + bash + core utilities
-RUN apt-get -y update \
-  && apt-get -y --no-install-recommends install \
+RUN apt-get update -y \
+  && apt-get install -y --no-install-recommends \
   cron \
   bash \
   ca-certificates \